Artificial tooth and backing therefor



I. DQFRANKEL.

ARTIFICIAL TOOTH AND BACKING THEREFOR.

APPLICATION FILED JUNE 7, 1919.

1,433,997. Patented Oct. 31, 1922..

Patented i Bl, 1922.

NITEDF STATES r :iiti

I JAMES D. FRANKEL OF CHICAGO, JILLINOIS ARTIFICIAL TOOTH AND BACKING; THEREFOR.

Application filed June '7, 1919. .Serial no. 302,42d.

tion, reference being had to the accompany,

ing drawings, forming a part of this specification.

My invention relates to an improvement in artificial teeth capable of being generally used in connection with practically all types of artificial restorations, such as crowns, fixed and removable bridge work, whole and partial plates etc., and briefly stated, my 1nvention contemplates:

1st, The provision of an artificial tooth, stronger mechanically and having better aesthetic qualities than the artificial teeth heretofore employed by the dental profession.

2nd. An artificial tooth provided with a backing so applied thereto that it is not visible on the labial (or buccal) surface of the tooth, or at any of the margins thereof,

and so remote from the incisal (or occlusal) surface of the tooth that when in the mouth 1t is entirely invisible.

3rd. The provision of artificial teeth, in-

terchangeably adaptable to a novel form of backing that may either be made by the practitioner for the particular case in hand, or furnished by the maker of the artificial teeth, as desire Y 4th. [an artificial restoration that is extremely sanitary in the mouth, and one which when employed'in a bridge makes with the gum the hair-line contact which is in conformity with the best prosthetic practice of the present dayQ 5th. The provision of a backing for an artificial tooth which does not to any appreciable degree increase the bulk of the lingual surface of the/tooth, and thereby interfere with the free movement of the tongue.

These and other objects of my invention will more fully and at large appear in the progress of the following description, wherein reference is made to the accompanying drawing, in which:

Figure 1 is a side elevational view of an upper incisor made in accordance with my invention.

F igure2 is an elevational view of the linp gual surface thereof;

Figures 3, 4 and 5 are res ectively isolated top plan, and rear and front elevational views of one form of my invention.

Figure 6 is a side elevational view of the incisor shown in Figure 1, with the backing of Figures 3, 4 and 5 applied thereto.

Figure 7 is a sectional view'of the same incisor, with'the backing applied thereto, this section being taken in a vertical plane at right angles to the labial surface of the tooth and diagrammatically illustrating the hair-line contact between the gum and the ridge lap of such tooth.

Figure 8 in a vertical section similar to Figure 6 illustrates a modified form of backing which extends partially over the socalled ridge lap of the tooth.

Figure 9 illustrates a form of backing that extends entirely over the ridge lap, being one which is particularly useful and desirable in connection with Richmond crowns and certain types of small bridges.

Figure 10 is a side elevational view of a bicuspid constructed in accordance with my invention.

Figure 11 is an elevational view of the lingual face thereof. v

Figure 12 is a side view of the same bicuspld, with a suitable backing applied thereto, the backing in this case not extend ing over the ridge lap of the tooth.

igure 13 is a vertical sectional view'of a bicuspid provided with a modified form of backing which extends partially over the ridge lap thereof, and

Figure 14: is a horizontal sectional view of a four-tooth bridge embodying teeth and cisors and bicuspids, it will be understood me that my invention may be applied to cuspids and molars, or any other teeth, with equal facility.

Referring first to Figures 1 to 9 inclusive,

at It I have illustrated an artificial tooth,

which while it may be made of any suitable material, is preferably made of porcelain, the tooth illustrated in these figures being a central incisor. As is generally known in the dental profession, in the manufacture of 11a backing embodying 60 45 4 are-designed to engage the backingiI-Shall be porcelain teeth by known methods, it is practically impossible to make two porcelain teeth, which are absolutely identical in all dimensions, without resorting to excessive grinding, which is av tedious operation and extremely expensive in quantity production. Minor variations are bound to occur, and these while perhaps indistinguishable to the eye, and seemingly insignificant, present serious difliculty when an attempt is made to make a plurality of teeth fit equally well in a single backing. One of the salient features of my invention consists in making artificial teeth and backings so that by very little but accurate grinding all teeth of a certain kind, in the same general class as to size, may surely be interchangeable in a backing that has been made to fit any one of them. The advantage of such an arrangement to the practitioner in the construction of a restoration and in making replacements is of course obvious.

Referring specifically to the incisor A of Figures 1 and 2, it will be seen that grooves BB are formed in the mesial and distal surfaces of the tooth. These grooves at all points along their length are substantially semi-circular in cross section, but are con- .Siderably'more shallow towards the incisal edge than towards the gingival margin of the tooth. Moreover, the said grooves diverge one from the other as they extend away from the gingival margin; Let it be assumed that the line XX of Figure 1 is drawn through the widest vertical plane of the tooth, extending from the mesial to the distal surface thereof. -It will be seen that the grooves B-B lie behind this plane, and

are thus invisible from the labial side of the tooth.

In accordance with one feature of my invention, all teeth of a certain kind and size are designed interchangeably to fit in a suitable backing therefor. It 18 desirable that those surfaces of the artificial tooth which uniform in size, shape and relative idisposition. Those surfacesof the tooth in Figures 1 and 2 which enga e the backing are the walls of the grooves B and the shut portion C of the lingual surface. These surfaces may be ground so that they are uni form in all teeth of the same kind and size.

The tooth shown in Figures 1 and 2 is designed to cooperate with the back'ng designated as a whole by the reference letter D. This backing which is of gold or any other suitable material, and which may be made by a casting, swedging or any other suitable process known to practicing and manufacturing dentists, is formed in one piece consisting of the pillars EE and What for lack of a better name may be termed, the band F. Thepillars are arranged to engage in the grooves BB of the tooth A with their outer. surfaces fiush with the mesial and distal surfaces of the tooth, so that said pillars when positioned in the grooves are invisible from the labial side of the tooth. The band F extends from pillars E-E around the mesial-lingual and distal-lingual margins, and snugly fits the ground surfaces of the shut portion C of the lingual surface.

It will be understood that the tooth is fitted into the backing as shown in Figure 6, and thereinsecured as by means of any suitable dental cement. Furthermore, it is apparent that the backing may be carried with or formed as a partv of a whole or partial plate, that a plurality of backings may be formed in one piece, soldered or otherwise secured together, and suitably attached to the abutments in bridgework," the backing formed integral with or secured to the band or coping of a Richmond crown, etc. These and other applica tions of my invention will be apparent to any person skilled in prosthetic dentistry.

The tooth and backing illustrated in Fig ures 1 to 7 inclusive has a number of features of distinct advantage from both a mechanical and aesthetic standpoint. The arrangement wherein the pillars E-E and their co-operating grooves BB are of less cross section towards the incisal edge than near ,,the gingival line is conducive to mechanical strength, since the tooth is of greatest bulk and consequently of greatest strength near its gingival surface. Moreover, the entire backing is not only invisible from the labial side of-the tooth, but is remote from the incisal edge, and therefore is not visible at theincisal edge, a feature particularly "advantageous when my'invention is applied to lower anterior.

' restorations. .'Moreover, the form of backing not only aroun the shut, but extends up onto the ridge lap as well, making a more 2 or less box like backing structure that is particularly strong, and'therefore desirable in many cases. That portion of the band which extends over the ridge lap may if des'red stop short of the labial-gingival margin, as shown, thereby not reducing the substantially V-shaped space between the ridge lap and the under surface of the gum.

In Figure 9 is shown a form of backing particularly desirable in connection with .crown is to be set. i

In any case, where the backing is to extend over the ridge lap of the tooth, that portion of the ridge lap designed to engage the backing is preferably ground, so that teeth of the same kind and size will surely be capable of beinginterchangeably mounted in the backing.

In Figures 10 to 12, both inclusive, l have illustrated a tooth and backing structure articularly applicable to bicuspids and moars. The bicus id shown in these figures, and indicated at is provided with grooves B- B corresponding to the similarly designated grooves of the teeth illustrated in the preceding figures. A ledge I located above the occlusal surface of the tooth extends around the lingual surface thereof, and around mesial and distal surfaces to the grooves 13-13, the lower ends of which terminate at the ledge l. The backing for this tooth is illustrated in position in Figure 12, and comprises pillars fitted in the grooves BB, and a band portion which fits snugly against said ledge and extends around the shut of the tooth, but does not extend over the ridge lap. In the modified arrangement shown in Figure 13, the backing band extends not only around the shut of the tooth, but over a portion of the ridge lap as well.

Attention is directed to the fact that the ridge lap of each of the teeth herein illustrated is inclined more or less sharply downward from the labial (or buccal) surface as the case may be. This insures a substantially V-shaped space between the ridge lap and gum, as clearly illustrated in Figure 7. This large V-shaped space is much more sanitary than would be a small space, or no space at all between the ridge lap and gum. Moreover, food naturally tends to slip from a sharply inclined ridge lap instead of adhering thereto.

in Figure M, is illustrated a four tooth bridge embodying teeth and backings constructed in accordance with myinvention. It will be seen that where two or more of the teeth of my invention are used in a bridge, and have their backings soldered or cast together, a considerable bulk of backing material is located between the teeth, (where it does not increase the bulkiness of the back or lingual side of the bridge), the general shape of the bridge being long and narrow.

Attention is directed to the fact. that the grooves in the mesial and distal tooth surfaces, as well as the pillars which fit therein are preferably of substantially semi-circular cross-section, since this arrangement afiords maximum strength for a given amount of material used in the pillars, at the same time minimizing the reduction of the amount of porcelain in the tooth due to the presence of the grooves; this arrangement moreover overcoming any tendency of the porcelain to chip ofi" of the walls of the grooves.

While I have illustrated my invention in a number of characteristic embodiments, it will be understood that it would be useless to attempt to illustrate and describe all of the embodiments of my invention. 1 appreciate the fact that. the specific construction of my improved restoration may be varied considerably in practice, and therefore do not limit myself to the arrangements herein shown and described, but desire to claim broadly all equivalent embodiments of the invention defined by the appended claims.

In the claims, when I refer to the grooves in the mesial and distal surfaces of the tooth as being downwardly diverging, I refer to the incisal or occlusal end as the lower end, regardless-of whether the tooth is intended for an upper or lower restoration.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is:

1. An artificial restoration comprising a tooth having the ridge lap thereof inclined sharply downwardly from the gingival margin to the shut. portion of the tooth, downwardly diverging grooves formed-in the proximal surfaces of the tooth and means for securing said tooth in the mouth with the gingival margin of the tooth making hair line contact with the gum and with a substantially V-shaped open space between the gum and the ridge lap of the tooth, said means comprising a backing having a pair of pillars engaging in said grooves and a band connecting said pillars.

2. An artificial restoration comprising a tooth having the ridge lap thereof inclined sharply downwardly from the gingival margin to the shut portion of the tooth, downwardly diverging grooves formed in the proximal surfaces of the tooth and means for securing said tooth in the mouth with the gingival margin of the tooth making hair line contact with the gum and with a substantially V-shaped open space between the gum and the ridge lap of the tooth, said means comprising a backing have a pair of pillars engaging in said grooves and a band connecting said pillars and extending around the shut portion of the tooth.

3. An artificial restoration comprising a porcelain tooth having the ridge lap thereof inclined sharply downwardly from its gingival margin to the shut portion of the tooth, together with a backing for said porcelain tooth whereby the same is suptact with the gum at the gingival margin,

7 and with a substantially V-shapedopen space between the gum and the ridge lap.

4. An artificial restoration comprising a tooth having vthe ridge lap thereof inclined sharply downwardly from the gingivalmargin to the shut portion of the tooth, downwardly diverging grooves formed .in the proximal surfaces of the tooth and means for securing said tooth in the mouth with the ingival margin of the tooth making hair ine contact with the gum, said means comprising a backing having pillars engaging in said grooves and a band connecting said pillars, said band extending over the ridge lap of the tooth andspaced from the gum to provide a substantially V-shaped open space between the gum and band.

5. An artificial restorationcomprising a porcelain tooth provided with an edge-like gingival margin and having the ridge lap thereof inclined sharply downwardly from the gingival margin toward the shut por tion of the tooth, downwardly diverging grooves formed in the proximal surfaces of the porcelain tooth, said tooth comprising arcuate lateral flanges which overlie said grooves, together with means for supporting said tooth in the mouth with its gingival margin making hair-line contact with the gum, and with a substantially V-shaped open space between the ridge lap and gum, said means consisting of a backing comprising a band lying around the shut portion of the tooth and pillars engaging in said grooves, the breadth of the shut of the tooth being less than the distance between said flanges,

the proximal surfaces of said backing 'con verging toward the lingualsurface of the tooth.

6. An artificial restoration comprising a porcelain tooth having downwardly diverg-' ing grooves formed in its proximal surfaces, the proximal portions of said tooth comprising arcuate flanges overlying said grooves, together with a backing comprising pillars lying in said grooves and a band extending around the shut portion of the tooth, said arcuate flanges lying around said pillars and effectually preventingthe latter from being sprung laterally out of said grooves.

7. An artificial restoration comprising a 

